In recent years, polymer materials have been used in various fields such as food packaging, machinery, and medical equipment, and demand for such polymer materials has been growing. A composite is one of the methods of high functionalization of polymer materials. “Composite” is a general term for complex materials produced by combining two or more different raw materials together. A microcomposite having a filler whose size is 1 μm or more, and a nanocomposite having a filler whose one of the three dimensions is about one to several tens of nanometers are exemplified as the composite composed of a polymer matrix and a powder filler and classified according to a filler size of the powder in the composite. In various types of composites, significant improvements of physical properties have been verified. Therefore, high functionalization of materials is expected from further development ahead.
As an example of a functional composite, it is described in Patent Document 1 that a composite having high wear resistance and low frictional properties can be obtained by dispersing a hard amorphous carbon powder (diamond-like carbon: DLC) as a dispersed material in a matrix such as a resin-based material, a metal-based material, or a ceramic material.
In Patent Document 2, it is described that a nanocomposite having nanoparticles which are uniformly dispersed as a dispersed material in a matrix can be obtained by using a graft polymer as the matrix without performing treatment for modifying the surface of the nanoparticles or adding a dispersing agent.
In Patent Document 3, a method for producing a nanocomposite is described saying that a nanocomposite can be easily obtained by mixing a matrix composed of an organic polymer such as an epoxy resin and a nanosized inorganic filler such as alumina as a dispersed material, and then uniformly dispersing the inorganic filler with the use of an apparatus such as a homomixer or a nanomizer.